This invention relates generally to knit hosiery, and more particularly to a circularly-knit sock with a targeted compression zones designed to lift and stretch the plantar fascia of the foot. In various exemplary applications, the targeted compression zones of the present sock may also function alone or in combination with other features to “lock” the sock in position on the foot of the wearer during use. In addition to improved fit and comfort, the present sock may enhance a runner's proprioception, kinesthetic awareness, stamina or endurance, and overall performance.